Process of jiggling liquid into discrete droplets



July 2, 1 968 D. A. HARRIS 3,390,835

PROCESS OF JIGGLING LIQUID INTO DISCRETE DROPLETS Original Filed Dec. 30, 1964 1 7 A 4' O f 5' FIG.

Z7 Z4\ 9% L i FIG.2

INVENTOR DAVID ALAN HARRIS ORNEYS ABSTRACT OF THE DISCLOSURE A process for treating or removing vegetation is described, and the process includes the steps of supplying a liquidcomposition in the form of a plurality of continuous streams which are vibrated at a frequency above 500 vibrations per minute so that the liquid streams are broken up into continuous streams of relatively coarse droplets whichare sufiiciently large to prevent spray drifting of the droplets. The plurality of liquid streams may each have a diameter in the range of 0.01 to 0.025 inch,

and the relatively coarse droplets may have diameters inthe range of 500 to 5000 microns.

This is a division of application Ser. No. 422,284, filed Dec. 30, 1964, now Patent No. 3,353,748.

This invention relates to a method and a sprinkler apparatus for treating vegetation and soil with liquids,

particularly liquid herbicidal compositions, and is a con- .tinuation-in-part of United States application, Ser. No.

216,139, filed Aug. 10, 1962, and now abandoned.

Modern methods of agriculture and horticulture require the application of many biologicallyactive substances to growing vegetation, either to kill the vegetation if it consists of weeds, or to kill harmful pests which live on the vegetation or in the ground. In many cases the treating substances are solid and the most convenient way of using them is to convert them into a suitable liquid formulation which is then applied by means of a sprinkler apparatus.

Various kinds of sprinkler apparatus for such liquids are known in which the liquid is discharged through a nozzle or nozzles which produce spraysof drops having a wide spectrum of drop size. For example, in the application of liquid herbicidal compositions to crops the practice has been for the composition to be applied from a crop spraying machine comprising a fixed tube provided along its length with a series ofspecially designed atomizer nozzles for the liquid. These nozzles result in the liquid being discharged with considerable force as a fine spray which contains drops whose sizes vary widely but containing a large proportion of very small drops, i.e., having average sizes of to 130 or 150 microns. The use in agriculture of such sprays leads to the problem of the small drops drifting on the wind anddamaging susceptible crops growing in the vicinity, and this is particularly serious where a herbicidal composition is applied...

The spray drift problem-referred to above is particularly serious where the herbicidal composition contains a hormone herbicide, for example a phenoxyalkanoic acid herbicide such as those commonly known by the abbreviations 2:4-D, MCPA, and CMPP which are used widely for selective weed control in cereal crops. The risk of damage from spray drift is so serious in some areas that spraying with hormone herbicides can only be carried out in still conditions. This often means that the herbicide cannot be applied when most convenient and, in some instances, it is not possible to use such products at all where a susceptible crop is growing in the vicinity of the cereal crop which it is desired to spray. However, despite this severe practical limitation on the use of herbicides, particularly the application of hormone herbicides, no satisfactory method of avoiding spray drift has hitherto been devised.

It has now been found that the problem of spray drift can be mitigated by use of the method and apparatus of this invention.

Accordingly, the present invention provides a method of applying a liquid, for example a herbicidal composition, wherein the liquid is supplied to a vibrating distributor having a number of discharge orifices for the liquid, the degree of vibration and size of the orifices being such that the liquid discharged from the orifices falls to the ground'as drops which are sufficiently large as not to result in any substantial spray drift.

The invention also includes a sprinkler apparatus for liquids comprising a distributor having an inlet through which the liquid can be supplied to the distributor, and a number of discharge orifices for the liquid, and means for vibrating the distributor so that liquid discharged issues from the orifices and falls to the ground as drops which are sufiiciently large as not to result in any substantial spray drift. Preferably the orifices are inclined to the vertical.

When liquid issues from the orifices it does not, as might be supposed, become shattered into clouds of fine drifting droplets by the violent action of the distributor, but instead the liquid forms large drops which, as indicated above, have little tendency to drift. This device is particularly suitable for use in weed control since it not only enables liquid herbicide to be applied with great economy with regard to the amount of liquid used, but in addition it permits efiieient weed control to be effected in areas in the immediate vicinity to growing crops without damage to them.

For low volume spraying within the range of about 2 to 25 gallons per acre, the liquid is preferably supplied under a constant head within the range of about 2 to 6 feet which can be achieved by a pump set to raise the liquid from a tank to the desired height before the liquid is piped to the distributor inlet. For spraying at volumes greater than 25 gallons per acre, the head, orifice diameter and degreev of vibration are accordingly increased. The means for vibrating the distributor is conveniently actuated mechanically, for example, by a cam or a crank, and, where the apparatus is used in conjunction with a tractor, drive for the crank or cam may be taken from the tractor power take-off via a propeller shaft. Alternatively, the means for vibrating the distributor can be actuated electromagnetically. If desired, the pump may be replaced by a tank having a capacity sufficient for the area to be sprayed and having a depth so that any variation in head due to a decrease in liquid level in the tank does not substantially affect the distribution of liquid.

The distributor is conveniently a perforated tube having closed ends and where it is desired to apply a liquid herbicidal composition, the tube is preferably arranged to be carried horizontally above the ground. Preferably the tube has two or more inlets for the liquid and, where two inlets are used, the inlets are disposed respectively adjacent the ends of the tube. The provision of two or more inlets produces a balanced liquid supply which serves to reduce pressure drop along the tube as well as liquid starvation to the nozzles due to the vibrating motion of the tube.

The discharge orifices can be a series of small holes drilled at various points along the length of the tube but, if desired, ceramic, plastic, or other nozzles may be fitted. During investigations, it was found that in general, drilled orifices result in the streams of discharged liquid breaking up into drops earlier than where ceramic nozzles are used; and drilled orifices produce a spray of greater cone angle, that is the degree of divergence of the spray, than the ceramic nozzles.

The selected size and disposition of the discharge orifices depend upon a number of factors including the viscosity of the liquid to be applied and the pressure exerted upon the liquid at the orifices. Hence, the dimensions preferred herein may be subject to some variation contingent upon the particular factors involved. Similarly, the optimum height at which the distributor is carried with respect to the surface to be sprayed will be subject to some variation depending on conditions. However, in order to produce a continuous non-drift spray, it is important that the liquid pressure be sufficient for the frequency and amplitude chosen, Also, pressure will affect the application rate and may have to be limited ac: cordingly.

The size and pitch of the orifices are governed by the application rate which is desired. For satisfactory liquid distribution, each cone of spray must overlap and the pitch is so chosen in relation to amplitude, pressure and orifice shape to give the required cone angle from each orifice.

Vibration frequency must be sufficient to give satisfactory liquid distribution and this is especially important where the liquid is discharged vertically downwards. Where the discharge is inclined below the horizontal, the liquid distribution is improved and the vibration frequency may be reduced.

The amplitude of vibration should be the minimum to give a good spray. If the amplitude of vibration is unnecessarily large, the drive will require more power and wear will be accelerated and on the other hand, if the amplitude is too small, an unsatisfactory liquid distribu' tion will result.

According to one form of this invention, the sprinkler apparatus comprises a distributor tube having two or more inlets through which it can be supplied with liquid and having discharge orifices of a diameter within the range of about 0.01 to 0.125 inch disposed in line along the length of the tube at a pitch within the range of about 1% to 4 /2'inches and inclined at an angle between about and 90 below the horizontal, and means for vibrating the distributor within an amplitude range of about 0.125 to 0.5 inch at a frequency of at least about 500 to about 2000 or 3000 vibrations per minute, (v.p.m.), to distribute droplets predominantly having diameters in the range of about 300 to 5000 microns. The

term vibrations per minute (v.p.m.) used in this specification refers to complete vibration cycles.

Preferably the orifices are inclined between 5 and 45 below the horizontal and, if desired, the distributor may have a certain number of orifices disposed to discharge liquid vertically and the remainder of the orifices disposed to discharge liquid at an angle inclined to the vertical. The discharge of liquid in a vertical direction is particularly suitable for spraying the ground around the base of such fruits as black currents and vines.

In one preferred form, it has been found that the following dimensions give excellent results: inch orifice diameter; 2 inches orifice pitch; an orifice inclination of 20 below the horizontal; /8 inch amplitude of vibration and a speed of vibration of 1100 v.p.m. to provide droplets, the bulk of which have diameters within the range of 500 to 1600 microns. Preferably the apparatus includes a supply tank from which the liquid is pumped at a certain pressure or raised to a certain head to give an equivalent pressure head, before being fed to the distributor inletts).

The inclination of the orifices between 5 and 45 below the horizontal results in the spray of liquid discharged developing a pattern to give "the required distribution at a minimum height above the crop to be sprayed. However, a good liquid distribution pattern is obtained even when the distributor cannot be maintained at a constant height above the crop to be sprayed and, generally, it is only necessary to provide sufiicient clearance to avoid the distributor striking the ground when used on rough land.

Conveniently, to avoid undue pressure drop and liquid starvation in the distributor tube it has been found that instead of a single tube, the distributor may usefully comprise four, or a larger number'of even smaller tubes, preferably each having an inlet'adjacent each end and arranged with their longitudinal axes in line. Where four tubes are used, the tubes are p'referably rigidly connected in pairs and,"for dynamic balance, each pair is caused to vibrate in opposite directions. Thus, at any one instant the two pairs are moving towards each other and at another instant the pairs are moving away from each other.

Further inventive features are included in the following particular description of sprinkler apparatus given by way of example with reference to the accompanying drawings, in which:

FIGURE 1 is an elevation showing a general arrangement of the sprinkler according to the invention;

FIGURE 2 is a diagrammatic view showing a liquid circuit for the sprinkler of FIGURE 1; and

FIGURE 3 is a transyerse sectionthrough the distributor tube -6=shown in FIGURE 1.

Basically, the present apparatus uses a pump to rats: liquid from a tank to a certain predetermined level so that th' liquid is supplied to a distributor under a constant head. he distributor is a tube drilled at various points along its length to form a series of discharge orifices which may be fitted with. nozzles,- and a'cam is employed to vibrate the distributor so that liquid discharged issues from the orifices as streams which are broken up so as to fall to the ground as a shower of drops.

FIGURE 1 is ageneral arrangement of the sprinkler having a tank 1 carried on a frame 2 which is constructed so that the sprinkler can be mounted on a tractor or other conventional machine. The distributor consists of four similar tubes designated as 3, 4, 5 and 6, respectively, which are suspended from the frame 2 by webbing fiexure strips 7 constructed to permit longitudinal vibratory movement in a direction indicated by arrows A and resist movement in a direction at right angles to the plane of FIGURE 1. Each distributor tube is drilled at various points along its length to form a series of discharge orifices. The discharge orifices may be disposed so that liquid is discharged either vertically or in a direction inclined to the vertical or, in certain circumstances, a combination of vertical and inclined'discharge may be used. FIGURE 3 shows the distributor tube 6 in crosssection with the orifices inclined at an angle a to the horizontal. The angle or may be within the range of O to below the horizontal. The two pairs of distributors 3-4 and 56 are respectively interconected by sleeves 8 and 9 so that the members of each pair vibrate in unison. Each distributor is supplied with liquid from the tank lthrough inlets 10 disposed adjacent the ends of the tubes and each pair of tubes is caused to vibrate by means of a cam 11. In FIGURE 1 the cam has two lobes but, if desired, four lobes may beused. The cam is mounted on a shaft 12 which runs in two bearings (not shown) and drive for the cam is taken from the power take-off of the tractor via a propeller shaft. The cam 11 has two followers 13 consisting of two sealed ball races which are mounted on push rods 15 and biased towards. the cam by helical springs 14. The push rods 15 are respectively connected to the pairs of distributor tubes by arms 16, and the push rods are slidab'ly mounted in bearings (not shown) housed in brackets l7 which are secured to the frame 2.

FIGURE 2 shows the liquid circuit for the sprinkler in which a pump 18 draws liquid from the base of the tank 1 through a suction filter 19 and, according to the setting of a control valve 20, liquid is directed through a, pressure sprayed at a rate of 25 gallons per acre.,The test was made in a wind having a speed of about 15 m.p.h. with the tractor travelling at 4 m.p.h. and it was found that young kale and potted tomato plants placed no more than filter 21 to a header P p The zz P 22.1135 .5 two feet away and down wind from the extremity ofthe outlets q one oft-the 'mlets The vibrating distributor were unaffected by .thespray. Furr g i thgclrcwt Fontrolkd by by'pass thermore, the apparatus provided an even distribution of L:: q i2g fi gfi gxfgrgg i gzfi ggza hormone weed killer during the'test. By way'of compari- The following tableindicates the results obtained by the apPhcanon'of the Same herblcldal composmon high speed photography using various combinations of 10 under identical weather conditions but using a convenorifices diameter, pressure head, amplitude of vibration, nona'l fixed e spraying machine havmg atomlzer speed of vibration and the number of inlets of a short zles resulted m severe damage of young tomato 39 test distributor tube. Each each of the runs listed in the kale P Placed away h end of the P QY table liquid was discharged vertically and the orifices were boom of the machlnedisposed at.a pitch of 2 inches in a distributor tube hav- The range p $116 obfalned using an apparatus In ing a nominal bore of in h, accordance with the present invention was measured and I Liquid Amplitude Con e Width MeetingPpint; Run No. Nozzle Head of Frequency Liquid Supply 4 from of Two Ad acent (feet of Vibration (v.p.m.) Qrifice Sprays Below water) (inches) (inches) Orifice (inches) 1' lz drilled tube... '2 1,100 Single side 4.0 2.5 1 1 1,100 do 1.1 5.1 A2 i g 1,600 Double sided entry. 1.27 6.7

Run 1 produced a wide cone angle and a continuous spray of substantiallyeven drop size. Run 2 produced a narrower cone than Run 1 with continuous spray and although it appeared that the ,sizes of the drops .were uneven they were sufiiciently large to be satisfactory. Run 3 produced a narrow cone and an even spray.

The following table sets out details of an apparatus in accordance with the invention employing drilled orifices inclined rearwardly to the direction of motion and at an angle of below the horizontal in a distributor tube having a nominal bore of /2 inch.

A field trial employing the sprinkler apparatus described above with reference -to the drawings and having specific dimensions as set out below was carried out with the apparatus mounted on the rear of a tractor.

Tank capacity: 50 gallons.

Distributor: Four tubes, two of 6 feet length and two of 3 feet length and each having a nominal bore of /2 inch were connected in pairs (as already described). Each pair consisted of one 6-foot tube and one 3-foot tube to give an overall distributor length of 18 feet. The distributor was set at a height of 2 feet above the ground.

Orifices: Drilled at a pitch of 2" having a diameter of ,6 inch and disposed to face rearwardly of the direction of travel at an inclination of 20 below the horizontal.

Vibration: Amplitude inch.

Means to provide vibration: A two lobe cam having a rise of A inch; driven from tractor power take-off via a propeller shaft.

Cam speed: 550 r.p.m., that is 1100 v.p.m.

Liquid pressure head: 4 /2 feet.

This apparatus was used to apply an MCPA hormone herbicide composition obtained by dissolving in water at a concentration of 4 pints per gallons of Water. With such dilutions theviscosity of the composition is not appreciably greater than that for Water end, in general, is in the region of l centipoise. The resulting solution was compared as described below with drops obtained using a.

conventional spray.

Details of apparatus in accordancewith the present invention:

Rate of application: 20 gallons/acre.

Pressure head: 4 feet 6 inches.

Distributor tube bore: /2 inch.

Orifice: Drilled at a pitch of 2 inches having a diameter of & inch and disposed to face rearwardly of the direction of travel at an inclination of 20 below the horizontal.

Vibration: Amplitude Vs inch at 900 v.p.m.

Details of conventional spraying machine:

Rate of application: 20 gallons/ acre.

Pressure head: Equivalent to 60 feet.

Nozzle: 1 ceramic tipped flat fan nozzle designated number 0.

In order to separate the drops and to facilitate accurate measurement thereof, both machines were run at a speed of 8 mph. This speed is slightly greater than that required to give a 20 gallon per acre rate of application but at the correct speed for this application the drops have a tendency upon impact with the ground to spread and coalesce which would lead to an incorrect measurement and accordingly the speed was increased to overcome this tendency. In order to measure drop size, the liquid was discharged onto a mixture of petroleum jelly and liquid paraffin, (The mixture containing between 24 and 30% petroleum jelly.) After the discharged liquid was collected on the petroleum jelly/paraflin mixture, further liquid paraffin was added so that any drops remaining on the surface of the mixture assumed spherical shapes. A count of drops of liquid discharged from each machine revealed that the bulk of droplets from the conventional machine had a diameter ranging between 60 and 130 microns whereas the bulk of droplets discharged from the present machine had a diameter within the range 500-1600 microns.

It should be understood that the foregoing example is illustrative rather than limiting on the invention, and that the present invention may be subject to various changes that will be apparent to those skilled in the art. Thus, while specific reference has been made above to hormone herbicides, the method and apparatus of this invention can be applied to fungicides and other herbicides, for example, the dipyridylium quaternary salt herbicides known by the common name diquat and paraquat and to insecticides such as the systemic organo phosphorus insecticide known by the common name menazon.

Further, some changes in the design of the present apparatus may be made without departing from the. spirit of the invention. For example, the sprinkler apparatus of the invention may be provided in the form of a device adapted to be mounted-on tractors and ,various Wheeled vehicles, or it may be provided as an integral unit on a tractor, trailer, or the like vehicle.

-It will thus be recognized from the foregoing description that the term mobile, when used in the claims herein, contemplates the use of both wheeled and non-wheeled apparatus, as will be obvious to one in the art. Accordingly, the invention should only be limited tothe scope of the appended claims.

What is claimed is:

'1. A process for treating or removing vegetation with a liquid composition which comprises the steps of supplying said liquid composition in the form of a plurality of streams having a diameter within the range of 0.01 to 0.125 inch, vibrating said liquid streams at a frequency within the range of at least 500 to about 3000 vibrations per minute whereby said liquid composition streams are broken up and discharged in the form of a continuous stream of relatively coarse liquid droplets having diameters within the range of about 500 to 5000 microns such that the droplets are sufliciently large to be substantially free of spray drift.

2. A process for treating or removing vegetation with a liquid composition which comprises the steps of supplying said liquid composition in the form of a plurality of streams having a diameter within the range of 0.01 to 0.125 inch, vibrating said liquid streams at a frequency within the range of at least 500 to about 2000 vibrations per minute whereby said liquid composition streams are broken up and discharged in the form of a continuous stream of relatively coarse liquid droplets having diameters within the range of 500 to 1600 microns such that the droplets are sufficiently large to be substantially free of spray drift.

3. The method of claim 2.wherein the liquid is supplied tothe vibrating step under a constant head within the range of 2 to -6 feet. 1

4. The method of claim 2 wherein the liquid is discharged -to the crops at an angle between 5 and below the horizontal. Y 1

- 5. The method of claim 2 wherein the amplitude of vibration lies within the range of A; to /2 inch.

i 6. Aprocess for treating or removing vegetation with an even distribution ofa liquid composition-which comprises thesteps of moving said liquid composition over ground having: said crops, dividing-said liquid-composition into streams from a plurality of liquid discharge orifices havinga diameter within the range of-at least 0.01 to 0.125 inch, said liquid composition beingdivided into said streams in a balanced manner with reduced pressure drop to avoid liquid starvation of said streams when subjected to vibrations, vibrating said orifices at a frequency of at least about 500 vibrations per minute and thereby breaking up said liquid streams into coarse liquid drops of substantially even size, said coarse liquid drops being sufliciently large to be substantially free of wind and spray drift, and causing said coarse liquid drops to fall to the ground in the form of continuous overlapping shower cones.

References Cited UNITED STATES PATENTS 2,405,357 8/1946 Siever 239-102 X 2,895,680 7/1959 Tavone. 3,162,368 12/1964 Choate et a1 239 4 X FOREIGN PATENTS 213,925 12/1953 Australia. 660,580 5/1938 Germany.

M. HENSON WOOD, JR., Primary Examiner.

V. C. WILKS, Assistant Examiner. 

